There are many sources of energy other than conventional fuels, such as solar, geothermal, waste heat from direct user sources. In many cases, the energy source is a low temperature energy source. For example, U.S. Pat. No. 5,551,238, issued Sep. 3, 1996, teaches the use of concentration energy in a solution, such as brine, to produce useful energy.
U.S. Pat. No. 4,214,170, issued Jul. 7, 1980, teaches a power generation-refrigeration system for extracting energy from a refrigerant with a turbine where the extracted energy is used to compress refrigerant and/or to generate electrical energy. The initial heat source is a low temperature heat source such as solar heated water or waste water from a manufacturing process. Three different heat exchangers and two turbine units are required, as well as a complex refrigerant flow system operating in a refrigerant mode or a power-generating mode.
U.S. Pat. No. 5,150,585 issued Sep. 29, 1992, also teaches a system for extracting energy from a refrigerant to generate electrical energy. The refrigerant is vaporized by the heat in a location to be cooled and additional energy is provided by a conventional compression process using a motor driven compressor before the vaporized refrigerant is passed through a turbine for converting kinetic energy in the refrigerant into electrical energy. The system taught herein also uses energy in cooling water supplied to the compressor to augment the energy in the vaporized refrigerant.
The systems described in the '170 and '585 patents require complex heat exchangers and piping or a motor-driven compressor in order to extract energy from the refrigerant. Accordingly, it is an object of the present invention to provide a relatively simple system with heat exchangers supplied from a single working fluid and without motor driven compressors in a normal operating mode for providing a refrigerated air flow while extracting energy from a refrigerant.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.